PTAB

IPR2016-01780

SpringPath Inc v. SiMPLiVity Corp

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Computer File System Data Structures
  • Brief Description: The ’799 patent discloses a stacked computer file system architecture. The system comprises a top-level "namespace file system" layered over a content-addressable "object store," where data objects are identified and accessed using content-derived "fingerprints," such as cryptographic hashes.

3. Grounds for Unpatentability

Ground I: Claims 1-2, 7-9, 12, 17-19, 27, and 35 are anticipated by Atkin under 35 U.S.C. §102

  • Prior Art Relied Upon: Atkin (Patent 7,747,663).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Atkin discloses every limitation of independent claims 1 and 19. Atkin teaches a storage system with a file system front-end layered over an underlying content-addressable storage (CAS) system, which corresponds to the claimed namespace file system over an object store. Petitioner asserted that Atkin's CAS generates a unique content address (a "fingerprint") for each data block ("object") by hashing its content, and these addresses are used to access the blocks. Furthermore, Atkin was alleged to disclose the required data structures, including inodes that represent files, an "imap" that maps inode numbers to the content addresses of the corresponding inodes, and directories that map file names to inode numbers. Petitioner contended that these structures in Atkin are themselves objects (data blocks) whose own content-based addresses are derived from their respective content, thus anticipating the claim limitations regarding how file, inode map, and directory objects derive their own fingerprints.

Ground II: Claims 11, 20, and 33-34 are obvious over Atkin in view of Li

  • Prior Art Relied Upon: Atkin (Patent 7,747,663) and Li (a 2004 publication titled "Secure Untrusted Data Repository (SUNDR)").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that to the extent Atkin does not explicitly disclose that its content-based addresses are cryptographic hashes (claim 11), Li teaches this element. Li's SUNDR system explicitly names all on-disk data structures using cryptographic handles, specifically 20-byte SHA-1 hashes. For claims 20 and 33, which require maintaining a location index mapping fingerprints to physical locations, Petitioner asserted that Li discloses a "bstor" index system that maps SHA-1 hashes to their physical disk locations. For claim 34, requiring mapping indexed by an offset, Li's disclosure of inodes containing SHA-1 hashes of file data blocks was argued to meet the limitation.
    • Motivation to Combine: A POSITA would combine Atkin with Li because both references address the same problem of enabling concurrent modifications in content-addressable file systems. A POSITA would be motivated to use Li’s well-known and secure SHA-1 cryptographic hash function to generate addresses in Atkin’s CAS system for added security, which was a simple and known design choice.
    • Expectation of Success: Petitioner asserted that implementing a known cryptographic hash function like SHA-1 into a CAS system like Atkin's would have been a matter of routine skill with a high expectation of success.

Ground III: Claim 10 is obvious over Atkin in view of Sandberg

  • Prior Art Relied Upon: Atkin (Patent 7,747,663) and Sandberg (a 1985 paper on the Sun network filesystem).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that dependent claim 10 adds the limitation of providing the namespace file system as a layer in a storage stack between a virtual file system (VFS) layer and a block storage abstraction layer. While Atkin discloses a layered system, Sandberg explicitly teaches a VFS interface designed to separate generic filesystem operations from specific underlying implementations. This VFS layer in Sandberg sits between client system calls and the underlying filesystem, creating the specific stacked architecture recited in claim 10.
    • Motivation to Combine: A POSITA would be motivated to add Sandberg's VFS layer to Atkin’s architecture to gain the known benefits of machine and operating system independence. Both references describe layered file systems that provide an interface to underlying storage. Combining them would be a logical step to improve Atkin's portability and provide more transparent access to clients, a common and well-understood goal in the field.
    • Expectation of Success: Petitioner contended that adding a well-known architectural component like a VFS to another layered file system was a known design choice that would have been obvious to try and required no more than routine skill.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 13 based on Atkin alone, arguing that its described Unix-like structure would have been understood by a POSITA to be POSIX-compliant.

4. Key Claim Construction Positions

  • "fingerprint": Petitioner proposed this term be construed as "hash value of an object's content." This construction was central to their argument, allowing the "content addresses" generated by hashing in Atkin's CAS system to be directly mapped to the claimed "fingerprint" limitation.
  • "namespace file system": Petitioner proposed this term be construed as "a file system that accesses data and metadata as objects that are referred to by name." This construction was used to argue that Atkin's file server front-end, which organizes and accesses data through named files and directories, satisfies the requirements of the claimed system.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-2, 7-13, 17-20, 27, and 33-35 as unpatentable.